Analysis of Layered Composite Skin Electro-Thermal Anti-Icing System

Elangovan, R.; Olsen, Ronald F.

doi:10.2514/6.2008-446

Cited by 15 publications

(7 citation statements)

References 11 publications

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“…This type of low power system was applied to an composite engine inlet by a large aircraft manufacturer. 3 The thermal anti-ice systems keep the protected surface temperatures above the water freezing point (0 • C). In most systems, the heating panels are distributed span wise and each one may have several independently controlled heating elements distributed stream wise.…”

Section: Introductionmentioning

confidence: 99%

Differential Boundary-Layer Analysis and Runback Water Flow Model Applied to Flow Around Airfoils with Thermal Anti-ice

Araujo

Jorge

Jesus

et al. 2009

1st AIAA Atmospheric and Space Environments Conference

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Certification regulations require safe flight under icing conditions, therefore, ice protection on aircraft wings and horizontal stabilizers will be necessary if critical aerodynamic performance degradation is to be avoided. The present paper developed a numerical code for prediction of heat and mass transfer in two-phase flow around aeronautical airfoils. These systems are equipped with thermal anti-ice systems that are designed to keep the surface free of ice as much as possible. The code is able to estimate the temperatures and runback water around the airfoil surface due implementation of heat transfer submodels in a baseline thermal anti-ice model: 1) it estimated the airfoil surface wetness factor by means of a runback water film and rivulets pattern flow models; 2) it evaluated the laminar and turbulent boundary layers with pressure gradient and laminar-turbulent transition over non-isothermal and permeable airfoil surfaces by performing integral and differential boundary layer analysis; and 3) it predicted the onset position and length of the laminarturbulent transition region with pressure gradient and turbulence level effects. The work followed a validation and verification process during the numerical code development. All submodels results were separately verified against experimental data. The numerical results of the thermal performance of the airfoil with the anti-ice baseline model, plus the present contributions, were validated against experimental data of an electrically heated NACA 0012 airfoil operating in the Icing Reseach Tunnel (IRT), NASA, USA. Nomenclature A= finite volume area exposed to flow around the airfoil, m 2 B h = heat transfer driving force B m = mass transfer driving force h = convective heat transfer coefficient,W/(m 2 · K) c p = specific heat, J/(kg · K) E = mechanical energy, J e = mechanical energy per unit of film width, J/m F = wetness factor F r = rivulets flow wetness factor F s = stream wise wetness factor G = mass flux ρ · u e , kg/(s · m 2 ) g(θ 0 ) = auxiliary function, −1/4 cos 3 θ 0 − 13/8 cos θ 0 + 15θ 0 /8 sin θ 0 − 3/2θ 0 sin θ 0 g m = mass transfer conductance, kg/(s · m 2 ) h = convection heat transfer coefficient, W/(m 2 · K) h = water film height at film break-up position, m h + = non-dimensional critical film height at film break-up position, (ρτ 2 h 3 0 )/(6µ 2 σ f g ) h 0 = critical film height at break-up position, m h r = rivulet height downstream break-up position, m h(x) = half rivulet height in function of its horizontal coordinate,R(cos θ − cosθ 0 ), m i = specific enthalpy, J/kg k = thermal conductivity, W/(m · K) m = mas flow rate, kg/s Ma = Mach number p = pressure, Pa p mixt = total mixture pressure, Pa p vap = partial vapor pressure, Pȧ q = heat flux, W/m 2 q lost = heat transfer rate lost to gaseous flow, W R = rivulets radius, m r = high speed aerodynamic recovery factor R m = mean rivulet radius within the finite volume, 1/2 · (R out + R in ), m R t = thermal resistance, K/W s = stream wise distance over airfoil surface, m St = Stanton numb...

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Section: Introductionmentioning

confidence: 99%

Differential Boundary-Layer Analysis and Runback Water Flow Model Applied to Flow Around Airfoils with Thermal Anti-ice

Araujo

Jorge

Jesus

et al. 2009

1st AIAA Atmospheric and Space Environments Conference

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show abstract

“…Currently, there are several well-developed anti-icing/de-icing systems for aircraft, including electric-impulse systems, electro-thermal systems, and hot air systems. [7][8][9] Meanwhile, new and innovative technologies, such as plasma jets, icephobic surfaces, and hybrid systems, have emerged and are showing promising developments. [10][11][12] A sound understanding of the adhesion between ice and substrate is critical for developing effective anti-icing/deicing systems.…”

Section: Introductionmentioning

confidence: 99%

Research on normal ice adhesion strength in icing wind tunnel

Wang

Xiong

Zhu

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part G:

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Aircraft icing seriously jeopardizes flight safety. The design of aircraft anti-icing/de-icing systems requires a thorough understanding of the adhesion between the ice and the substrate. In this research, an experimental device that can be housed within a wing is designed and constructed. Simulation analysis of the interfacial stresses is performed, which reveals that increasing the load and the interface size led to a deterioration in the uniformity of stresses at the interface. In addition, the ice layer does not undergo cohesive damage during the tests. The normal ice adhesion strength is evaluated in an icing wind tunnel using the methodology outlined in this paper. Glaze ice exhibits an increase in normal adhesion strength at lower temperatures, whereas the trend is reversed for rime ice. The minimum adhesion strength occurs near the medium volume diameter (MVD) of 30 µm. Furthermore, the normal strength is significantly enhanced by increase in wind speed and surface roughness, as well as by surface painting. The adhesion strength of aluminum substrates to ice is greater compared to titanium and stainless steel. Compared to shear adhesion strength, normal adhesion strength is less sensitive to various influencing factors. The proposed experimental framework provides precise measurement of normal adhesion strength of impact ice in the icing wind tunnel.

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“…Flight practice shows that when an aircraft passes through clouds containing supercooled water droplets, ice accretion may occur on the windward surfaces of its key parts (wing, engine or windshield) due to droplet impingement [1,2]. Without effective protection measures, icing will worsen the lift and drag characteristics of the aircraft, reduce its stall angle of attack, stability margin and maneuverability [3][4][5], posing a serious threat to flight safety. Icing detection is the prerequisite and basis for the operation of aircraft icing protection systems, and its effectiveness and accuracy are crucial.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Optimum Design of Aircraft Icing Detection Based on Large-Scale Icing Wind Tunnel

Ding,

Yi,

et al. 2023

Aerospace

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Icing detection is the premise and basis for the operation of aircraft icing protection system, and is the primary issue in flight safety assurance. At present, there is a lack of research methods and design reference for the layout optimization of ice detectors. Therefore, in order to simulate the real icing environment encountered by the aircraft more accurately, a large-scale icing wind tunnel was used to carry out experimental research on the icing characteristics of the sensor probes. A closed-loop experimental method including the typical condition selection, sensor array interference examination and ice shape repeatability verification was initially proposed. A stepwise optimization process and a sensitivity analysis on ambient conditions were combined to determine the optimal distribution for sensor installation. It is found that the water collection coefficient on the cylinder surface of the probe first increases and then decreases along the axial direction, reaching the extreme value at a certain position. The height of this extreme point will gradually increase with the development of the wall boundary layer, showing a variation range of 2~30 mm. Improper design may cause the sensor probe to fail to capture the point with the maximum icing thickness, affecting the sensitivity of icing detection. In addition, each probe position has different sensitivity to changes in flow parameters; the points with larger icing mass and lower sensitivity to changes in attack angle will have better detection effect. The measured data and analysis in the present work can provide a basis for the accurate design of icing sensor probes.

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Analysis of Layered Composite Skin Electro-Thermal Anti-Icing System

Cited by 15 publications

References 11 publications

Differential Boundary-Layer Analysis and Runback Water Flow Model Applied to Flow Around Airfoils with Thermal Anti-ice

Differential Boundary-Layer Analysis and Runback Water Flow Model Applied to Flow Around Airfoils with Thermal Anti-ice

Research on normal ice adhesion strength in icing wind tunnel

Experimental Study on Optimum Design of Aircraft Icing Detection Based on Large-Scale Icing Wind Tunnel

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